Fly Fishing Leader Design

by | Jan 6, 2021 | 10 comments

Beginning anglers probably don’t give much thought to the overall composition of their leaders. With so much to learn and dissect, the novice focuses mostly on fly choice, fly rods, reels or lines. That’s fair. Because fly fishing is a complicated endeavor. And it makes sense to follow basic advice, grab an extruded, knotless leader from the fly shop and get to work on learning some things about fly fishing.

Then, somewhere down the winding path of a seasoned angler, we’re finally ready to consider the leader. With a fundamental understanding of casting, and some good ideas about trout behavior, we start asking questions about the means of delivery. We finally start to consider the leader, realizing that leader composition is the most important element in presenting the fly.

What follows is not a comprehensive consideration of leader design. Instead, this is a continuation of the Troutbitten short series, Know Your Weights and Measures. The goal here is to highlight the stats to be understood — to give a wide perspective of what matters in leader design and how materials and construction affect the angler’s ability to deliver and drift the fly.

READ: Troutbitten | Know Your Weights and Measures (Part One)

READ: Troutbitten | Distance — Know Your Weights and Measures (Part Two)

Let’s do it . . .

What Matters?

Material diameter and material stiffness: these are the two qualities that come into focus. And along with length, these properties dictate the performance of a leader.

Breaking strength matters very little. Certainly, it’s good to know that our fly is tied to four pound or ten pound test, because that fact dictates how hard we fight a trout or pull on a greedy tree limb. But given the wide variety in leader materials, breaking strength has virtually no predictable correlation with diameter or stiffness.

Material diameter and material stiffness. That’s what matters. And these two qualities determine a leader’s turnover power and the amount of potential drag.

Photo by Josh Darling

Turnover vs Drag

Remember this: At the heart of every good leader design is an intentional balance between turnover and drag.

Thicker and stiffer material gives more power and push to a leader. 2X carries the power of our cast with more force to the end of the line, while 6X has far less punch. (Likewise, a thicker butt section carries more power than a thinner one.)

But that same 2X tippet drags more than 6X. And it may create that drag in three different places: on the surface, under the surface and in the air. Being both thicker and stiffer, 2X is more influenced by water currents than 6X. Likewise, the thicker 2X simply weighs more, so it hangs more and sags more in the air. And as always, sag equals drag.

A well-designed leader is a calculated balance between the counterparts of turnover and drag.

Diameter and Stiffness

Most anglers focus first on the tippet. And that’s a great place to start.

We should know the diameter of our tippet but consider its flexibility and stiffness too. Rio Suppleflex nylon, for example, is much softer than Cortland Premium Fluorocarbon of the same diameter. So it carries less turnover power but also incurs less influence from the water.

This kind of education starts by making no assumptions. On your next few trips to the river, spend a half hour testing things for yourself. Tie your fly to 2X and then 6X. You’ll see quickly that the results are undeniable. And knowing how to match your tippet to the fly size and/or fly weight is a skill gained from these kinds of tests on the water.

Remember, terminal tippet is not the only consideration. And the full leader should be understood. So try using thick butt sections vs thin ones. On-the-stream testing, without bias, is the best way to gain a fuller picture.

In my favorite Harvey dry leader, I often adjust the last three tippet pieces on the water. For example, if I swap out from a #18 Blue Winged Olive to what I call Light Dry Dropper, with a #14 X-Caddis paired with a #20 WD40, then I cut back the 3X, extend the 4X and finish with a piece of 5X of about 24 inches. Then I trail with 6X flouro to the small WD40. Without these adjustments, I will not get the preferred s-curves to the dry fly.

This example is not for you to slavishly imitate, but to see what might be necessary to change on the water. How do I know what to alter in my rig? It comes from experimentation. I remember reading George Harvey’s explanation of how to adjust leaders for each fly. But try as I might, I didn’t understand the process until I put it into practice. It takes an advanced angler’s mindset and a willingness to adjust.

Photo by Josh Darling

Of course, there are keys to understanding leaders and lengths too. The longer, softer and smaller the diameter of a material, the less power it has for turnover. And remember the corollary: thinner diameters take on less drag from currents, on the surface or below it.

All of this is equally important for underwater presentation of nymphs and streamers.

Take the popularity of euro nymphing tactics for example. I prefer a Mono Rig instead of a euro fly line because it’s much lighter, so it sags less than a comp line.

But I also prefer a Mono Rig butt section that is thick enough to be powerful in the cast. Turnover is paramount to me. So I’m not a not a fan of micro-thin butt sections, as they are underpowered, and they encourage lobbing more than casting of the flies.

Likewise, I build my standard sighter from materials that are a little stiffer and more powerful than the bi-color material found in fly shops. Then, I often add a length of the bi-color material to extend my sighter, during times when I’m tight lining further away.

READ: Troutbitten | Fly Fishing the Mono Rig — It’s Casting, Not Lobbing

A Word On Taper

Tapering a leader reduces the power created from a fly line. That’s its job — to dissipate power evenly.

This makes a lot of sense for presenting dry flies fine and far off. But it makes very little sense for many underwater presentations.

This understanding seems to have taken hold in the streamer world, as most of the recommended steamer leaders these days have very little taper, being composed of just a few diameters at most. But this is not the case with many nymphing leaders, especially for a tight line.

I do not want long tapers in my tight line leaders. When I’m casting a Mono Rig or even a euro line, I want to get all the power possible from these thin lines. So I don’t want a long taper. Remember, tapers are for dissipating power. But I want turnover power, and I’m trying to get that from a relatively thin line. People tend to take standard leader design principles over to tight line leaders. And in my opinion, that’s a mistake.

Photo by Josh Darling

Next Time

Understanding the diameter and stiffness of the materials in your leader is critical to taking the next step as an angler, because nothing affects the performance of our flies more than the leader itself. Knowing the composition of the leader, and adapting it with intention to specifically suit your own goals, is at the heart of next-level fishing.

All of these weights and measures are intertwined. And in the last part of this Troutbitten short series, I’ll address what we should understand about flies and weights.

Fish hard, friends.


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Enjoy the day.
Domenick Swentosky


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Domenick Swentosky

Central Pennsylvania

Hi. I’m a father of two young boys, a husband, author, fly fishing guide and a musician. I fish for wild brown trout in the cool limestone waters of Central Pennsylvania year round. This is my home, and I love it. Friends. Family. And the river.

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What do you think?

Be part of the Troutbitten community of ideas.
Be helpful. And be nice.


  1. You have written a lot about your preference to cast the fly over lobbing the fly. Can you help me understand the benefits of casting over lobbing? I find lobbing to be very accurate. What am I missing out on? Thank you. I enjoy your articles and reading about your experience.

  2. Domenick, it might be helpful to take a look a some science to provide an even deeper understanding of leaders and turnover. Specific gravity of your material has a lot to do with it based on momentum. Once you have the specific gravity then the volume comes into play. The diameter of the line determines the volume by cross section. It might lead to the conclusion that stiffness is actually not what it seems. I’d be happy to share what I’ve learned about the subject

    • Hi Jeff,

      Thanks for the thought. I absolutely acknowledge that there’s a much deeper world than I know about regarding these monofilaments. But, honestly, I don’t think anglers care much about that.

      How would we gauge the specific gravity of a leader material on the water? And volume?

      I have respect for the science behind it all. And I think it’s an interesting thing to study. But as anglers, we are looking for things we can measure and understand quickly to make changes on the water. No one wants to be away from the actual fishing for very long.

      I’m sure you are correct. I’m sure that stiffness may not be what it seams. But it’s enough for me to know that a stiffer line turns over better. And it’s enough for me to know the diameter and have expectation about how that will affect my casting and drift. I think that’s enough for most of us.

      I hope you see where I’m coming from. Not at all challenging your accuracy — as I’m sure you are right. I guess I’m speaking to practicality.

      Still open to learn more though . . .


  3. Nice article. The one thing that I struggle with is determining the stiffness of prospective tippet material. There is no measure except experience. For example, I’ve been trying to find 10 lb. Stren for sighter material in a mono rig. Haven’t been able to locate any so I’ve been looking at the yellow or orange Suffix but I’ve been reluctant to pull the trigger and commit to a spool of 330 yds. for $15 because I have no way of gauging it’s stiffness. Any thoughts?

    • Hi Andy,

      First, you can find Gold Stren pretty readily online. It’s linked to on all of the Mono Rig formulas you find here on Troutbitten. Just click on the orange link.

      Second, Suffix is fine. It’s actually a bit stiffer.


  4. Dominick, as usual great article. Thank you for “going deeper”. The devil is in the details and at its core physics and material science matter but as you say most want to know what fly to put one while others delve into the details. For me simple….great fun.

  5. I like this miniseries! I like to geek out over distance, weights and leader design too. It reminded me I need to do something about the hinge of my commercial sighter section. Keep up the great work!


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Domenick Swentosky

Central Pennsylvania

Hi. I’m a father of two young boys, a husband, author, fly fishing guide and a musician. I fish for wild brown trout in the cool limestone waters of Central Pennsylvania year round. This is my home, and I love it. Friends. Family. And the river.

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